The present invention relates to a conveyor belt formed of plastic links, the links having a substantially rectangular outline and each carrying on two parallel sides thereof spaced sleeve-like ears provided with openings; The ears are each fitted into the spaces between the ears of adjoining links, with the openings of the links being aligned with each other and articulated to each other by means of inserted transverse rods which are locked in the axial direction thereof within the or lateral side ears.
Recently, applicant's company and other manufacturers have marketed link-type conveyor belts, especially plate-type or "flat top" conveyor belts in which the links are made of plastics material, for example polyamide, and in which the links are articulated together by means of inserted transverse rods or bolts. The supporting parts of the conveyor belt are termed the "links", thereby to indicate that they constitute plate-shaped or skeleton-type components which are each of a width to occupy a specific part of the conveyor belt width. In addition to a true rectangular shape, the links may be also of an approximately trapezoidal shape so as to be suitable for curved conveyor belts. Preferably, the ears are closed, sleeve-like structures. Alternatively, however, these parts, termed ears, may be formed with a jaw-like configuration, i.e. to be closed only partially, without departing from the principle of design.
U.S. Pat. No. 4,069,911 shows a known link-type conveyor belt in which the transverse rods interconnecting the links are secured in position by set screws threaded into a threaded hole at either end. In this structure, it is disadvantageous that the forming of threads in plastic injection molded parts requires a complicated injection mold subject to failure and trouble, which mold necessitates extended dead times and, thus, increased cost owing to the operations of unscrewing the threaded insert, which must be made at the time of mold release.
Further, the set screw used as a locking means may easily become loose as a result of continuous movement, such that the set screw, in turn, must be provided with safety locking means.
It is therefore the object of the present invention to facilitate insertion and locking of the transverse rods, while completely avoiding elements projecting beyond the lateral sides or above the conveyor surface. Likewise, threaded elements should be omitted, i.e. the design should orient itself particularly by the possibilities of the plastic material and provide for low-cost manufacture and repair.
These objects are solved in a link-type conveyor belt of the type outlined at the beginning, wherein the openings of the lateral side ears are closed by a peg or dowel inserted from the side with its full length to act as a locking element. The opening of each lateral side ear is provided with recesses extended in a direction transverse to the axis of the opening and defining vertical locking surfaces. The peg or dowel is provided on part of the length of its shank with a pair of resilient tongues each defining a wedge-shaped abutment as counter-locking surface, wherein the locking surfaces overlap each other with positive engagement in the locked position.
The element termed "peg" (or dowel) is inserted into the lateral opening with a tight fit, in which connection the means being known for peg or dowel techniques may be used for securing. The peg is inserted into the opening with its full length. The inner diameter of the opening is equal to that of the remainder of the ears. More particularly, the opening is wide enough to freely receive the transverse rod to be inserted.
The peg may be provided with one or more slits and/or recesses in at least part of its length. These provisions permit the peg to be compressed in its outer profile, so as to engage the opening with increased clamping force.